Associated sleep effects of nocturia
Nocturia causes a person to wake during the night one or more times in order to urinate. It is acknowledged to be clinically relevant and have significant impact upon patients when two or more voids are experienced per night. Nocturia repeatedly fragments sleep, and is one of the most troublesome of lower urinary tract symptoms.
Nocturia and nocturnal awakenings are associated with multiple negative outcomes, including significant reductions in quality of life, and an increased risk of morbidity and mortality.
Equally common
There have been multiple studies of nocturia prevalence in adults around the world. Nocturia is equally common in men and women, and although it increases with age, it affects a significant proportion of younger as well as older people. On average, up to around 20 per cent of adults aged 40–59 years have ≥2 voids per night. This increases to around 35 per cent in those over 60 years.
The condition is often trivialised and assumed to be an inevitable part of the ageing process. However, research has now shown that this is a serious disease which, if not treated appropriately, can have social, health and economic implications for patients, their families and society.
Causes of nocturia
Nocturia can be a result of external factors such as drinking excess fluids before bedtime or taking certain medications. Nocturia is also associated with some medical conditions such as diabetes mellitus, diabetes insipidus and coronary heart disease.
Once these factors have been excluded, a urological aetiology of nocturia may be suspected in the majority of individuals.
These patients can be broadly categorised into those with a reduced capacity of the bladder to hold urine, and those with an overproduction of urine during the night (nocturnal polyuria), although there are many patients with a combination of these factors.
A minority of patients may have an overproduction of urine during the day and night (24-hour polyuria), and these patients warrant further investigation.
Up to 80 per cent of patients with nocturia have nocturnal polyuria. In healthy individuals, vasopressin (antidiuretic hormone) levels increase at night to reduce the amount of urine produced. This limits the need to empty the bladder during sleep. In many people with nocturia, the levels of vasopressin fail to rise, resulting in excess urine production and the need to wake during the night to urinate.
Family members
Nocturia can have a severe impact on a person’s overall quality of life. Sleep is extremely important for both physical and mental wellbeing and it is generally recognised that achieving adequate sleep can have a restorative effect.
Studies have shown that insufficient or disrupted sleep can lead to physical and mental problems, including depression and mood alteration. Indeed, poor sleep is reported to be associated with disrupted endocrine and immune functioning, reduced health and increased mortality. Interruption of the sleep cycle may be especially damaging if individuals are forced to get up during the first third of the night when they are in a deep stage of sleep. On average, individuals with nocturia experience the first void of the night two-to-three hours after sleep onset.
Family members are often woken up or disturbed when individuals visit the toilet during the night, and the negative effects of nocturia on sleep are therefore also relevant for other members of the household.
Risk of falling
Tiredness and getting up during the night can also lead to an increased risk of falling and accidents, particularly in the elderly, which can have severe consequences including bone fractures. The risk of falling rises from 10 per cent in those without nocturia to 21 per cent with three or more voids per night.
Furthermore, a recent study found that nocturia is an age-independent risk factor for hip fracture, suggesting that it may not be just elderly individuals with nocturia who are at risk of falls and fractures.
Nocturia can be an indicator of more serious underlying conditions, such as diabetes mellitus and cardiac problems, which may themselves lead to an increased risk of mortality. Recent research has suggested that there may be a link between nocturia and increased mortality, which is independent of such comorbidities.
As such, nocturia could be an early biomarker for underlying disease, but it is also possible that the impact of nocturia on sleep contributes to the relationship between nocturia, poor health and mortality. Further studies in this area are warranted.
Reduced productivity
Fragmented sleep, as caused by nocturia, not only affects the patient and their family but can also affect society as a result of reduced productivity and job performance. In a study published in the British Journal of Urology International in 2003, the condition was estimated to cost European businesses €3,700 per year for each sufferer as they were found to be 9.2 per cent less productive than other individuals.
Nocturia is under-reported since many people assume the condition is either part of the normal ageing process, too minor to seek help, or are unaware that the problem can be treated.
However, if nocturia is affecting the individual’s daily life, and even in some cases if it is not, a full evaluation is warranted due to the impact that the condition can have on sleep, quality of life and potentially health (see Figure below).
History-taking, physical examination and laboratory tests can help to exclude many rare but serious associated medical conditions such as diabetes mellitus and congestive heart failure, which must be diagnosed and managed appropriately. In some patients, factors such as sleep problems may play a role.
Accurate diagnosis of the causes of nocturia is crucial to selecting appropriate treatment and achieving a clinically meaningful reduction in nocturnal voids. If no serious comorbidities are present, and nocturia cannot be attributed to excessive evening fluid intake, information gained from a frequency–volume chart (FVC) is helpful in guiding treatment decisions.
Treatment of nocturia
Clinicians often assume that nocturia is a symptom of bladder storage problems due to overactive bladder (OAB) or benign prostatic hyperplasia (BPH), and prescribe traditional therapies for these conditions (for example, anticholinergics and α1-blockers).
However, data from several high-quality randomised controlled trials consistently show that these therapies (which target daytime urinary symptoms) fail to achieve a meaningful reduction in nocturia compared with placebo, even when reductions are reported to be statistically significant.
This is likely to be due to the fact that nocturnal polyuria is present in the majority of patients with nocturia (60–80 per cent). Patients may have nocturnal polyuria alone, or in combination with OAB and/or BPH. Nocturnal polyuria requires antidiuretic therapy (desmopressin) to reduce the volume of urine produced overnight. Patients with nocturia caused by nocturnal polyuria who have concomitant daytime symptoms may benefit from combination therapy that addresses all contributory factors.
Desmopressin
Desmopressin is a synthetic analogue of the naturally occurring antidiuretic hormone. It is recommended for people whose nocturia is caused by nocturnal polyuria and helps reduce nocturia by increasing the re-absorption of water in the kidney, which in turn decreases urine production.
(Source: IMT)
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